The astronomy is the Science of the observation of the stars, seeking to explain their origin, them evolution, their properties Physique S and Chimique S. It should not be confused with the Celestial mechanics which is only one particular field. With more than 6.000 years of History, origins of astronomy going up beyond the Antiquity, in the prehistoric religious practices

Astronomie comes from the Greek grc αστρονομία ( grc άστρον and grc νόμος ) what means law of the stars .

Astronomy is one of rare sciences where the amateurs can still play an active role. It is indeed practiced as leisure near many people of astronomers amateurs: the most impassioned and tested of them take part in discovered of Astéroïde S and of Comet S. It is on this subject a particularly popular leisure in France, as the Nuit testifies some to the stars .

History

See also: History of astronomy

Astronomy is regarded as oldest of sciences. The Archéologie reveals indeed that certain Civilizations disappeared from the Bronze Age, and perhaps from the Neolithic , had already knowledge in astronomy. They had included/understood the periodic character of the equinox S and undoubtedly their relationship to the cycle of the seasons, they could also recognize some Constellation S. modern astronomy owes its development with that of the Mathématiques since the Greek Antiquité and with the invention of instruments of observation at the end of the Moyen-âge. If astronomy were practiced during several centuries parallel to the Astrologie, the Century of the lights and the redécouverte of the Greek thought saw being born the distinction between the reason and the faith, so that astrology is not practiced any more by the astronomers.

Antiquity

At its beginnings, astronomy consists simply of the observation and the prediction of the movement of the Celestial objects visible with the naked eye. Nevertheless we owe with these different Civilization S from many contributions and discovered S:

In High antiquity

  • Preliminary:

    • Useless to specify it: if all the observations were done with the naked eye, the old ones were helped in this task by the absence of industrial pollution and especially luminous. For this reason, the majority of the observations to the antique would be impossible today.
    • One should not be mistaken there, these observations sometimes relatively simple seemingly (simple drawing of four or five stars), suppose already a high projection in the Civilization, namely the existence of an at least gathering unit:
    • : a writing or at least of its outline, one (proto-writing gathering jointly a whole of signs representing the principal objects and events) and a “system” including/understanding a Cosmogony, a Cosmology, a known sky chart without forgetting a Calendar (sometimes very developed) and a observatory, this one often rudimentary. Without these preconditions, of Astronomical observation under no circumstances would it exist recordable.
    • During Thousand-year-old S, astronomy was not separated from the Astrologie, which was the primum besides - movens . The divorce will intervene only with the Century of the lights to remain nowadays.
  • the systems best known if not most developed are:
    • with the Neolithic : all the large circles megalithic are in fact of the astronomical observatories, quote most known: Nabta Playa old of 6  000 with 6  500 years and Stonehenge (Wiltshire, England) 1  000 years later. Flammarion, which included/understood it one of the first, will speak about the megalithic circles about “monuments with astronomical vocation” and about “observatories about stone”.
  • at the beginnings of the History:
    • in the Old world:
      • Indian astronomy and Chinese: thus, the Rig-Veda mentions 27 Constellation S associated with the movement with the Sun as well as 13 divisions zodiacales with the sky.
      • astronomy sumérienne, and its derivative astronomies Chaldée, Mésopotamie, Egyptian and Hebraic. So that the Bible contains a certain number of statements about the position of the Ground in the Univers and on the nature of stars and planets.
    • in the new world, astronomies Amerindian born also already are very developed in particular the Toltèque, the Zapotèque (enough near) and the completely original Maya. Thus, without any optical instrument, astronomy Maya had succeeded in describing with precision the phases and eclipses of Venus!

In traditional Antiquity

  • old the Greek contributes important shares to astronomy, in particular the definition of the system of magnitude. Thus, the Almageste of Ptolémée (90 - 168) contains already a list of forty-eight Constellation S.

  • For to sail on sea but also in the Désert, the Arab Civilization S needed very precise data. Derived from Indian astronomy , Arab astronomy will culminate in 500, with the Âryabhata which presents a mathematical system chump end copernician, in which the Ground turns on its axis and considers the movement of the Planet S compared to the Sun. This nearly 1.000 years before the Occident!

The Middle Ages

At that time, astronomy cannot be studied without the contribution of other sciences which are complementary and necessary for him: mathematical (Geometry, Trigonometry), as well as the Philosophy. It is used for calculation of the Temps.

On sciences and education in general with the Middle Ages:

See also: Science of the Middle Ages, medieval Education, Sciences and technology Islamic

Early middle ages

It is necessary to announce the role of Boèce like founder as of the 6th century Quadrivium, which includes the Arithmétique, the Géométrie, the Musique and astronomy.

After the cruel invasions, astronomy develops relatively little in Occident.

It is on the other hand flourishing in the Muslim world as from the 9th century:

  • the Persan astronomer Al-Farghani (805 - 880) written much on the movement of the Celestial body S; It carries out a series of observations which enable him to calculate the obliqueness of the ecliptic;
  • Al-Kindi (801 - 873), philosopher and encyclopedic scientist, writes 16 works of astronomy;
  • Al-Battani (855 - 923), astronomer and mathematician;
  • Al-Hasib Al Misri (850 - 930), Egyptian mathematician;
  • Al-Razi (864 - 930), scientific Iranian;
  • Al-Farabi (872 - 950) large philosopher and scientist.

At the end of the 10th century, large a observatory is built close to Teheran by the astronomer Al-Khujandi.

The Philosophy (Plato and Aristote) formed integral part, with the whole of other sciences (Medicine, Geography, Mechanical, etc). Of this great movement of rebirth called golden age of the civilization arabo-Moslem woman .

See also: Islamic Civilization

Saint Bède Worthy the at the 8th century developed in Occident the Liberal arts (trivium and Quadrivium). It lays down the rules of the Comput for the calculation of the movable feasts, and for the calculation of the Temps, which required elements of astronomy.

Other elements were introduced in Occident via Gerbert d' Aurillac (Sylvestre II) a little before the An thousand, with the philosophy of Aristote. It is difficult to know exactly which Moslem astronomers were known of Gerbert d' Aurillac. Gerbert is important for the comprehension of the historical development of the whole of the Western knowledge, which included the Philosophie.

The low Middle Ages

The work of Al-Farghani is translated into Latin at the 12th century, at the same time as many other Arab treaties and than the philosophy of Aristote.

See also: the Middle Ages

In the Muslim world, one can quote:

  • in Persian, Omar Khayyam (1048 - 1131), which compiles a series of tables and reforms the Calendrier;
  • Ibn Al-Haytham (965 - 1039), mathematician and arabo-Islamic physicist;
  • Al-Biruni, (973 - 1048), mathematician, Astronomer, encyclopedist, etc;
  • Al-Tusi (1201 - 1274), philosopher, mathematician, Astronomer and theologist (regarded as one of the founders of trigonometry);
  • Al-Kashi (1380 - 1429), in current Iran and Ouzbékistan.

One can still quote Al-Maghribi, Al-Been enough.

Rebirth

During the Rebirth, Copernic proposes a heliocentric model solar system. This idea is defended, extended and corrected by Galileo and Kepler. Galileo imagines the Telescope to improve his observations. Being based on statements of observation very precise facts by the large astronomer Tycho Brahé, Kepler is the first to imagine a system of laws governing the details of the movement of planets around the Sun, but is not able to formulate a theory going beyond the simple description presented in its laws.

It is Isaac Newton which, while describing the Gravitation by its laws of the movement, makes it universal and finally makes it possible to give a rational explanation to the movement of planets. He invents also the telescope reflectors, which improves the observations.

Contemporary time

It is discovered that the star S are very remote objects: the star nearest to the Solar system, Proxima of the Centaur, is with more than four light-years.

With the introduction of the Spectroscopy, one shows that they are similar to our Sun, but in a great range of Température, Masse and size. The existence of our Galaxy, as a unit distinct from stars, is proven only at the beginning of the 20th century because of existence of others Galaxie S.

A little later one discovers the Expansion of the universe, consequence of the Loi of Hubble, establishing a relation between the speed of distancing of the others Galaxie S compared to the Solar system and their distance.

The Cosmologie makes great progress during the 20th century, in particular with the theory of the Big-bang, largely supported by astronomy and physics, like the cosmological thermal Rayonnement (or fossil radiation), and the various theories of Nucléosynthèse explaining the abundance of the chemical elements and of their Isotope S.

In the last decades of the 20th century, the appearance of the Radio telescope S, Radioastronomy, and means of Data-processing treatment, authorizes new types of Expérimentation S on the Celestial body S moved away, by spectroscopic analysis of the emission lines emitted by the Atome S and their different Isotope S at the time of the quantum jumps, and transmitted through the space by the electromagnetic waves.

Disciplines of astronomy

At its beginning, during antiquity, astronomy consists mainly of the Astrométrie , i.e. the measure of location in the sky of the star S and the Planet S. Later, from work of Kepler and Newton Celestial mechanics is born the which allows the mathematical forecast movements of the Celestial body S under the action of the Gravitation, in particular the objects from the Solar system. Most of work in these two disciplines (astrometry and celestial mechanics), carried out before with the hand, is now strongly automated thanks to the Ordinateur S and with the sensors CCC, so much so that now they are seldom regarded as distinct disciplines. Henceforth, the movement and the position of the objects can be quickly known, so that modern astronomy is concerned much with the observation and the comprehension of the physical nature of the celestial objects.

Since the 20th century, professional astronomy tends to separate in two disciplines: theoretical Astronomy of observation and astrophysical. Although the majority of the astronomers use both in their research, because of the various talents necessary, the professional astronomers tend to specialize in one or the other of these fields. The astronomy of observation is concerned mainly by the data acquisition, which includes the construction and the maintenance of the instruments and the treatment of the results. Theoretical astrophysics is mainly concerned by the research of the observational implications of various models, i.e. she seeks to include/understand and to predict the phenomena observed.

The Astrophysique is the branch of the astronomy which determines the phenomena Physique S deduced by the observation from the stars. Currently, the astronomers have a whole a formation pushed in astrophysics and their observations are almost always studied in an astrophysical context. On the other hand there exists a certain number of researchers and enquiring who study the Astrophysique exclusively. The work of the astrophysicists is to analyze data of astronomical observations and to deduce some from the phenomena Physique S.

The fields of studies of astronomy are also classified in two other categories:

  • By prone, generally according to the area of space (for example, galactic astronomy) or the type of problem addressed (formation of stars, cosmology)
  • By the mode of observation, according to the type of detected particles (light, neutrino) or the wavelength (radio, visible light, infra-red).

Disciplines by subject

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Astrophotography

Photographs taken since a telescope.

Disciplines by type of observation

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